Push plug for electric sockets



J. BLACKBURN PUSH PLUG FOR ELECTRIC SOCKQTS Filed Deo.

W. wv# M. MA W Patented 0st. 9, 1923.

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JASPER BLACKBURN, OF ST. LOUIS, MISSOURI.

PUSH PLUG- FOR ELECTRIC SOCKETS.

Application filed December 20, 1920.

To all t0/wm t may concern.'

Be it known that I, JASPER BLACKBURN, a citizen of the United States, and resident of the city of St. Louis and State of Missouri, have invented certain new and useful Improveniente in Push Plugs for Electric Sockets, of which the following is a specification containing a full, clear, and eXact description, reference being had to the accompanying drawings, forming a part hereof.

This invention relates to improvements in push plugs for electric sockets and has for its primary object a push plug which can be inserted in the ordinary screw threaded electric socket, thus eliminating the additional screw plug, which is now necessary with all push plugs.

A further object is to construct a push plug for the ordinary screw threaded elec tric socket which can be readily inserted and which can be withdrawn easily and thus do away with the danger of tearing down the socket in which it is attached, or of destroying the electric cord.

Al still further object is to construct a push plug` for electric sockets, which is composed of two sections,-the sections being springheld so that 'the same can be pushed together or made smaller while being inserted in the socket.

In the drawings:

Fig. 1 is a side elevation of the socket with parts broken away and in section showing my device located therein.

Fig. 2 is a vertical cross sectional view of my improved plug showing the position as sumed by the several parts when the plug is removed from the socket.

Fig. 3 is a bottom plan view of the plug.

Fig. 4 a face view of one of the sections of the plug showing the manner of securing the side contact therein.

In the construction of my device I employ a socket consisting of the shell 5. Within this shell is placed the insulator 6, and secured within the insulator is the socket proper. This socket consisting of the porcelain member 7 and the screw threaded shell 8, the screw threaded shell 8 also acting as one of the conductors. Mounted centrally in the porcelain member 7 is a conductor or contact insulated from the screw threaded shell 8. The plug consists of the members 10 and 11. These members are formed of insulating mapoint 9, This contact point is, however,

Serial No. 431,858.

terial and have their bottom edges 12 tapered, as indicated in Figs. 1 and 2. To these edges 12 is secured a spring plate 13. This spring plate is provided with a central opening 14 through which the cord 15 projects. The member 10 is provided near its bottom edge with a projecting lug` 16. This lug has an opening 17 formed therein. This opening is to permit the passage of the cord 15 and the function of the projection or lug 16 is to prevent the contact of the cord 15 with the edges of the opening 14 formed in the spring plate and prevent the wearing of of insulation. The member 11 is provided with the recess 18. This is for the purpose of allowing movement to the projection 16, as this projection is moved simultaneously with the members 10 and 11. The members 10 and 11 are each provided with a central groove 19, which terminates in an outwardly flaring opening 20 near the upper edge. The upper edges of the members 10 and 11 are inclined so as to form part of a helix, the member 11 being provided with an integrally formed bead 21. The purpose of this bead being helical in form is that it will correspond with the threads formed in the screw threaded socket or shell 8. Secured to the member 11 and located in the groove or opening 19 is a bracket 22, one side of which is secured to the member 11, the other side projecting inwardly. This inwardly projecting side is provided with an opening through which a pin 23 passes This pin is provided on both ends with a head and is surrounded with a coil spring 24. The purpose of this pin is to contact with the contact point 9 and allow the electric current to pass into the angle 22. To the lower end of the angle or bracket 22 is secured the end 25 of one of the wires forming the cord 26. Imbedded in the member 10 is a metallic contact plate 26. This plate has its upper portion projecting and extending from the side of the member 10. The extending portion 27 of the plate 26 is turned outwardly and arranged in the form of a partial helix so as to correspond to the screw threads formed in the shell 8 and to the lower end of the plate 26 is secured the end 28 of the other wire composing the cord.

It will be noted from Fig. 2 that the ends 25 and 28 are connected to their respective Contact portions in different vertical planes so that there will be no possibility of the binding screw by which these wires are secured coming in contact with each other and causing a short circuit. It will also be noted from Fig. l that the member lO projects above the edge 27 of the contact plate 26 so that there will be no possibility of inserting the plug in such a manner as to cause a short circuit; that is, to bring the edge 27 in contact with the contact point 9 and with the screw threaded shell 8. The purpose of mounting the contact. pin 23 in a yielrring or spring-held manner is to allow a variation of the depth of insertion of the plug within the socket, and also to do away with the necessity of jamming the plug tightly against the upper portion of the socket in order to get a perfect Contact.

Having fully described my invention, what l claim is: I

l. A push plug for electric sockets comprising a spring plate, a plug member formed of insulating material secured to said plate, a bead helically arranged around the upper outside edge thereof, a yielding contact point secured to thel inner edge thereof, a second section of insulating material secured to said spring plate and spaced apart from the lirst mentioned section, a contact plate secured to the outer surface thereof and near the upper end, said contact plate projecting outwardlyfrom the section and having its projecting edge helically shaped, and binding screws for securing electric conductors to the Contact plateV and yielding contact point.

2. A push plug for electric sockets comprising a pair of spaced apart insulating members having outwardlyr and upwardly inclined bottoms, a yielding Contact secured to one of said members and extending between the upper ends of said members, a Contact carried by one of said members, and a spring plate for yieldingly connecting said members at their lower edges.

In testimony whereof, l have signed my name to this specification.y

JASPER BLACKBURN. 

